Slotted vs. Plain rotors.... yes, yes, I have searched

[evo_ski]

Hey guys, just looking for some opinions from people who have actually USED slotted rotors. I have seen so many opinions floating around on the web that it is starting to make my head spin. Some people say that slotted rotors cannot be turned, while others say they can, some people say they give an odd pedal feel and eat your pads really fast, etc.

Right now I have stock 1.8t brakes with centric premium rotors and stoptech street performance pads. No real complaints other than the fact that the brakes just aren't big enough and I would like to upgrade. I purchased s5 brakes for the front, so I am going to need to pick up b6/7 s4 rotors to fit up front, and have a line on some s4 rear calipers that would be going on at the same time as well. Should be a pretty good upgrade, however, I am just looking to get the best rotors the first time around. What I am mainly looking for is an increase in wet weather performance. Right now when I step on the brakes after not having applied them for 2-3 miles or more in moderate rain it feels like it takes about a full second to even start to do anything and doesn't get full braking power until about 2 seconds after I press the pedal. That makes me INCREDIBLY nervous in certain situations.

I have heard that slotted rotors can help eliminate that slow initial bite in the rain, which is the only reason I am considering them. I am NOT considering anything that has been drilled because they take away too much pad surface, can crack, I don't like the look as much as slots (although 0% of this upgrade is for looks, I am going for safety and performance 100%), etc.

So my questions are as follows, hopefully someone that has used both plain and slotted rotors while keeping their calipers consistent can chime in since I already know all of the hearsay and opinions on the matter:

Do slotted rotors really make a decent difference in initial bite/stopping distance in the wet?

Do they give you an odd or juddery pedal feel?

Can they be turned?

Will I really need them, or should going to s5 fronts and b6 s4 rears, and stainless lines be plenty? I am debating between powerslots or the centric premiums.

I would prefer if people that have experience with these issues chime in rather than just opinions because I have read about every speculative opinion under the sun on the issue already.

Thank you very much in advance!

[ricekikr]

Do slotted rotors really make a decent difference in initial bite/stopping distance in the wet?

Do they give you an odd or juddery pedal feel?

Can they be turned?

Didn't feel any difference in the rain. But I also never felt that stock brakes were inadequate in the rain, they always bit instantly even in torrential rain. Stopping distance, the tires have always locked up / engaged ABS when braking hard in the rain in any car, so no difference.

When new, mine made a chug chug chug sound, even after bedding in (using Hawk method). Did a couple more bedding in cycles, sound was gone. Sounds/feels like stock rotors.

HTH

*this is on a b5, if that matters.

[tchuck]

...

1) Do slotted rotors really make a decent difference in initial bite/stopping distance in the wet?

2) Do they give you an odd or juddery pedal feel?

3) Can they be turned?

4) Will I really need them, or should going to s5 fronts and b6 s4 rears, and stainless lines be plenty? I am debating between powerslots or the centric premiums.

...

My other car is an Infiniti FX 35, and about a year ago I swapped the (blank) oem rotors on borh cars to slotted versions. The FX got R1 (Centric premiums) slotted rotors with Stoptech pads and the A4 got Adams slotted rotors with EBC green stuff pads. My impressions and answers to your questions are as follows:

FX:

1) No. The improvement in feel and stopping power is uniform in all conditions. When coming out of the car wash I still get a half second of slippy brake feel.

2) No. They feel exactly like the blanks.

3) Not sure, but in my area turning them is about $10/rotor cheaper than replacing, so I wouldn't even consider it.

A4:

1) No. The improvement is uniform in all conditions. That improvement, btw, was much less noticeable than with the FX. Also, EBC greenstuff pads are horrible and I will never buy them again. Very noticeable loss in braking performance post-install and extremely susceptible to fade in extreme circumstances.

2) No. They feel exactly like the blanks. They may be a generating a little more dust than the blanks, but I wouldn't put money on it. I may just be paying closer attention now.

3) see previous #3 answer.

The reasons I bought them were twofold; Curiosity and aesthetics. My curiosity is satisfied (no real difference) but I still like the way they look. Whether or not I get them again will depend on what kind of deals I can find next time I'm in the market.

Hope that helps. :thumbup:

[boostedAvant]

Go home Brett, you're drunk.

[ingolstadta4]

I've bought drilled and slotted rotors once. Never again! They can't be turned! Get s4 brakes instead.

[SlickFix]

Do slotted rotors really make a decent difference in initial bite/stopping distance in the wet?

Yes!

Do they give you an odd or juddery pedal feel?

No, not if you bedded your pads in correctly.

Can they be turned?

No idea. If they can't, then I'll just buy new ones when they need it.

Will I really need them, or should going to s5 fronts and b6 s4 rears, and stainless lines be plenty?

Need? No. Want? Yes.

I have experience in going from oem to slotted in both my old B5 A4 and Wifey's B6 Avant.


You're welcome.

[kneel]

Save the few extra $$ and get plain rotors, good pads and SS lines. THe larger brakes F&R will be more than enough improvement over the stock brakes

[DiertyEuroSpec]

I've had drilled/slotted S4 rotors both F/R rotors turned. The thing is I had to go to a slew of different places and was told "Oh no you can't turn those" and "No we don't turn drilled / slotted" But the truth is most of those places simply didn't want to turn them because the drilled / slotted effect wears their lathes must more then blank rotors. I finally found a local Mineke or Midas don't remember to turn them. Threw the guy $20 each under the table and he was happy and I was happy as well. Been on my car for about 10k no problems braking is smooth as butter. These rotors also came as part or a complete S4 brake upgrade and I couldn't be happier with it!! Since those rotors came as package deal I went with them but on my next I will be going for some blank OEM S4 discs or the ATE Premium One rotors look pretty enticing as well. Most S4 guys go with the plain rotor b/c they say it helps increase pedal feel / responsiveness.

[Ori0n]

I think your pad has a lot to do with wet conditions. Sometimes you can't get away from it though.

[texasboy21]

I was torn between slotted and plain rotors and opted for the plain. More surface area to make contact with the pads, and the money saved was put towards GoodRidge lines which I highly recommend.

[evo_ski]

Thank you everyone for your posts and experience. That is exactly what I was looking for. The pads I bought for the front are Hawk HPS, but I have yet to purchase the rear calipers. I will likely go with the HPS on those as well though if I do pull the trigger.

The initial slippery bite feel I only notice on the freeway. I have never noticed slow brake bite on regular 35-45mph roads, but when I am going 70 on the freeway it definitely makes me a little nervous sometimes.

Anyone have any recommendations on rotor brands? I have been looking mostly at the Centric Premiums. Thank you all very much!

[texasboy21]

Thank you everyone for your posts and experience. That is exactly what I was looking for. The pads I bought for the front are Hawk HPS, but I have yet to purchase the rear calipers. I will likely go with the HPS on those as well though if I do pull the trigger.

The initial slippery bite feel I only notice on the freeway. I have never noticed slow brake bite on regular 35-45mph roads, but when I am going 70 on the freeway it definitely makes me a little nervous sometimes.

Anyone have any recommendations on rotor brands? I have been looking mostly at the Centric Premiums. Thank you all very much!

Zimmerman

[tchuck]

Centric makes probably 75%of the rotors you'll find. Unless you want two-piece then I wouldn't worry about "upgraded" brands.

Your slippy feeling on the freeway could be your caliper piston sticking. I definitely have never experienced anything like what you described.

[evo_ski]

Awesome, that is excellent to hear. Hopefully you are correct and that by swapping out my calipers I should be good. I did hear a significant creaking noise when at a dead stop when I would modulate the pedal during warm days this summer. That is what originally prompted the brake upgrades.

[EBG 18T]

I have run slotted rotors for 15 years with mixed results. If using a quality blank (certric) they work out well, but on a cheap blank I had odd deposit issues. Currently I run Alcon scallaped rotors and very happy. The other nice thing about slotted rotors is it keeps the pads cleaner/fresh.

[MikTip]

Drilled and slotted are trickle down items from the racers/race cars.

So if you track your car, then maybe...but you will quickly find OE brakes & OE pads dont handle track events very well.

On a street driven car drilled and or slotted its purely for show.

[oaybar007]

I've had slotted rotors paired with Hawk HPS pads on my car for about four years now and I really don't feel any difference between these rotors and stock. The Hawk HPS pads are great and bite hard regardless but slotted...nothing special if you ask me. My brakes still suck in the rain. The pedal feel is still junk and my car still feels like it weighs a ton.

[Charles.waite]

Go home Brett, you're drunk.

LOL. I thought they'd gotten rid of these spammers. Awesome post to have copypasta'd though...

Brett you probably know as I've posted before, but I ended up going with plain centric rotors all around on my car. They quality is top notch to my untrained eye. The S4 fronts are heavy as the largest but sacks you're ever seen though. I finally moved the box with the 2 fronts put of my front hallway (the fiancé was getting pissed because the "stupid box" was in the way) and I nearly strained my back carrying them down to the basement.

Well that's an exaggeration but still.

Personally, I'd go with plain rotors. Slotted/drilled rotors are almost all for show in a street car. I'd take the difference in cost and get a tyrolsport brake kit or stainless lines. Probably provide a much more noticeable improvement for the money...

[tchuck]

... I'd take the difference in cost and get a tyrolsport brake kit or stainless lines. Probably provide a much more noticeable improvement for the money...

^That's true. I have all three.

[scapegrace]

excuse my ignorance but could someone explain what turning rotors is? from reading the previous posts, it sounds like its similiar to rotating your tires but for the rotors...and also why you would not be able to do this with slotted/drilled rotors.

I was also looking into getting slotted rotors mainly for aesthetic purposes (since i will need new brakes soon) but after reading some of these posts it sounds like mixed opinions on stopping feel with them. I always thought there really wasnt a difference in performance on the street level.

[EBG 18T]

excuse my ignorance but could someone explain what turning rotors is? from reading the previous posts, it sounds like its similiar to rotating your tires but for the rotors...and also why you would not be able to do this with slotted/drilled rotors.

I was also looking into getting slotted rotors mainly for aesthetic purposes (since i will need new brakes soon) but after reading some of these posts it sounds like mixed opinions on stopping feel with them. I always thought there really wasnt a difference in performance on the street level.

Rotors are placed on a lathe to remove material and re-level the surface. Many shops will not turn drilled or slotted rotors ince the chance of damaging the bit on the lathe is higher.

[SlickFix]

^^ Right, since the bit is stationary they have to "turn" the rotors around the bit.

[CyberPMG]

I've been happy with my slotted rotors. If you're only doing regular street driving, slotted/drilled rotors are probably overkill and would be more for show. If you plan to take it to the track once in a while and do some high spirited driving on some twisty backroads, then they slotted rotors will be a benefit as the slots will help to keep the brake pad surface clean (will wear down a bit faster) and the channel of the slot will allow any gas buildup from the brake pad friction to escape and not cause the pad to float over the rotor.

In normal driving, there's no difference in pedal feel between regular and slotted rotors. Only under hard braking, you may feel some pulsing in the pedal as the pads go over the slots, but it's not enough to make any difference in how you apply the brake pedal.

Your biggest bang for the buck improvement in brakes are with the brake pads and fresh brake fluid. The brake fluid should be changed out every two years regardless of miles. Over time, moisture gets into the braking system which will alter the brake fluid to a lower boiling point (quicker brake fade) and reduced initial bite. Always use DOT4 approved brake fluid when doing your flush and fill.

There are lots of choices for good brake pads... many depend on your style of driving. The Hawk HPS is a good a popular brand. I'm a fan of the Carbotech Bobcat pads for street use. There's many good threads on here that focus on different types of pads and how they perform.

For upgrading rotors, you may want to go with some Zimmerman rotors for ease of use and the ability to have them turned if needed down the line. I was able to get my slotted rotors turned once. Only one shop in the area was willing to do it. When I got it back, I had shadows of where the slots used to be. The rest of the rotor was turned down enough that I basically was back to a regular non-slotted rotor.

[BARRY]

in my experience slotted rotors and good pads do give a nicer initial bite. the major point of the slots are to clean off a layer of pad material so brakes have a fresh layer to make contact with the rotor. i've never experienced any brake shutter with quality slotted rotors/pads.

something to note, going with slotted rotors, and upgraded pads will induce higher amounts of pad dusting.

since you did state you are upgrading the size of your brakes, honestly with a good pad you won't need slotted or drilled rotors. larger brakes are exactly what the B6 A4 needs. in regards to your brake bite issue...it is probably due to the heat coefficient of the pads on your car. some pads higher in metal will require more heat before any "bite" occurs. this is where looking at heat range charts for pad choices become very important.

[DaSkorpion]

I'm loving the bite and feel of the ATE premium one rotors with HPS pads on a B7 S4 setup on my B6. NAM had a sale on these rotors a while back that is if you're interested in them. I picked up a set for nothing (pretty cheeeep) with free shipping and magically received them next day.

[B6A4Dave]

Hate to bump an old thread...however, I've been seriously looking at some braking upgrades to my car..

I'm currently on B5 S4 Fronts, stock lines, some O'Reilly brand pads...and for the first week or so I had these brakes they had tons of bite and felt very good at all speeds..

However, here I am, a few months later and they feel just like my old stock brakes did...yet they're noisy...annoying and heavy.

Regardless, I'm looking at changing Pads, Bleeding my brakes with Motul and getting some Goodridge lines..

So, I'm curious as to how much benefit people see out of Goodridge lines, does it really help? or is it one of those "felt feel" things and actually has no viable benefits other than 1) you know you have SS lines, and 2) the placebo effect of a stiffer feeling pedal makes you think you can stop.

And I see plenty of brake threads, but didnt want to start a new one... Thoughts on pads for a Street vehicle that sometimes gets spiritedly driven? EBC? Hawk? etc?

[texasboy21]

Motul fluid, Goodridge lines and Hawk HPS pads will feel great. SS lines make the pedal feel super firm, and to me gives more feedback.

[B6A4Dave]

Now, my only thing is on the pads, I've used Hawk on past cars and they absolutely Ate rotors, destroyed them quickly and made a lot of noise.

Any other pad suggestions? Understand I do mostly street driving and dont race....why race a Tank...pointless

[Johnny1.8T]

Right now im running the stock B6 brakes with Hawk ceramics and slotted rotors from adamsrotors.com. I think total i paid $550~ for everything front and rear. Ive had them for around 20k miles or so id say. The pads still look like they have the same amount of meat as they did when they were brand new. The rotors are in good shape too. I get a little bit of squeaking here and there, but its not bad. As for the performance in the rain, i havent noticed any sort of "lag" or "delay" when applying the brakes for the first time in a couple miles. IMO ive never liked the idea of turning rotors. In my head i think of it like "okay, so im taking my rotor and shaving it down, therefore removing metal. If im removing metal, i must be making the rotor weaker in some way. I may be running the risk of warping them easier than i normally would". I understand that when you turn rotors you really arent removing a lot of material, but to me, id rather just replace it. To each their own though!

[EBG 18T]

Now, my only thing is on the pads, I've used Hawk on past cars and they absolutely Ate rotors, destroyed them quickly and made a lot of noise.

Any other pad suggestions? Understand I do mostly street driving and dont race....why race a Tank...pointless

Hawk HPS are relatively easy on rotors. Carbotech 1521 (Bobcat) are very easy on rotors with similar bite to HPS. Potorfeild R4S are very low dust, a little more than Hawk HPS but more bite than HPS while still fairly easy on rotors.

[mobilesuit818]

This is my setup on my DD...with habitual midnight canyon runs...

Stock rotors(Brembo/Centric Premiums) with stock calipers.
SS Lines
Ate DOT 5 Fluid
Porterfield R4S

I race sometimes at the track and Porterfields have been consistent. These pads have great initial bite and almost zero brake fade (you would have to come to a dead stop from 50mph x 15-20 times before you even start to fade)

The only downside is that the brakedust but its a non issue cause I wash my car religiously wash my car every weekend, rain or shine.

The trick is to keep get rotors that are nice and thick, not cheapo ones. Also, your tires are what really stops your car, so make sure you get tires with great treadwear.

I run TW of 200 or less, and I can make my passenger kiss the dash.

[boy412]

My only complaint about them was the pedal feel. Sometimes I would notice it being a bit "juddery" as you describe it. But otherwise they were OK. I'm only buying non-slotted/non-drilled rotors these days. I never had them turned so can't comment on that. The slots seemed to have no adverse affect on pad life. I was running hawk HPS pads on my B5 S4 setup at the time.

[DaSkorpion]

I've been hearing great things about the Porterfield R4S pads...seems I might have to give 'em a try one of these days.

[CyberPMG]

This is my setup on my DD...with habitual midnight canyon runs...

Ate DOT 5 Fluid

Hope you meant DOT 4 fluid. Our brake system is not designed to handle DOT 5 (silicone). Only exception is the Motul 5.1 fluid which is DOT 4 compliant.

[JEENYUS]

i love my drilled rotors. Mercedes uses drilled rotors on their stock cars; i've never seen any manufacture sell slotted rotors on their stock cars. personally i went with drilled because i figured if Mercedes was using them, then there shouldn't be any negatives to using them. also, slotted rotors will wear your pads down faster and for me that is a negative. i know how in theory they clean the surface of your pads, but so does 1 second of braking at 50mph.

[mobilesuit818]

Hope you meant DOT 4 fluid. Our brake system is not designed to handle DOT 5 (silicone). Only exception is the Motul 5.1 fluid which is DOT 4 compliant.

I did mean DOT 4.

IMHO,
I am big fan of stock brakes(maybe cause I am frugal) but I honestly believe the engineers that designed our cars know what they are doing. BBK tends to mess up the balance of the car. With me its all about balance.

Having experience in track racing(go-karts, time trials, autocrossing, gymkhana, and drifting), you really only need big brakes if you are driving to the limit AND have sticky tires. I see guys everywhere who have big brakes but crappy tires.
It really defeats the purpose, cause you can have the biggest 6 Pot calipers with the best rotors, paired with crappy tires, you wont be stopping anywhere and flat spotting your tires.

With respect to the Cross Drilled/Slotted, my experience with them is that if you are going with a stock setup(A4/S4/Toureg), then stick with Stock thick blanks.
Your brakes are only as good as the amount of surface area the brake pads come into contact with the rotor. With Cross Drilled/Slotted, the surface area of the pad to rotor contact is severely compromised by at least 10%. On top of that, your structural integrity is also compromised, hence why Drilled/Slotted rotors have a much higher (almost tripled) propensity to crack/fail.
The other portion is the cost of the Drill/Slot Rotors are almost 40-50% more expensive.

Just like with everything else, its all about a pissing contest, and who has the biggest BBK etc, which I dont get or participate.

I choose functionality without compromising safety or performance any day.

On my current B6 with stock rotors and calipers, coupled with SS lines, DOT 4 fluid, Porterfields R4S Pads, and very sticky Hankook RS3 Tires, I have out braked my other friend's Stock B6 S4, stock B7 S4 numerous times at the track and in the mountains.
For the Daily Grind, I probably have avoided so many accidents, and at the same time brakes work so good, that you could literally brake check someone as you would be able to outbreak alot of car that are on the streets.
This is cheapo setup is cause you are just making the stock stuff work smarter and better.

Big brakes are nice and all, but for an average Lee(i'm asian) like me, stocks brakes work just perfect.

[texasboy21]

On my current B6 with stock rotors and calipers, coupled with SS lines, DOT 4 fluid, Porterfields R4S Pads, and very sticky Hankook RS3 Tires, I have out braked my other friend's Stock B6 S4, stock B7 S4 numerous times at the track and in the mountains.

Youre basically saying the upgraded pads on your stock brakes, trumped a brake setup with rotors that are 57mm larger and dual piston calipers?? Ehhh I dont think I can believe that one.

[Matt Devo]

Youre basically saying the upgraded pads on your stock brakes, trumped a brake setup with rotors that are 57mm larger and dual piston calipers?? Ehhh I dont think I can believe that one.

for a single stop, tires trump all (or most)

[EBG 18T]

Good pads and tires are the key. But in reality a non direction straight veined small rotor can't dissipate the heat fast enough from repeated hard stops, at that point you have exceeded the limit.

For street use many of us have recommended good pads, tires and the Tyrol brake stiffening bushing kit. This works great for daily driving and auto-x plus it is affordable.

Or those of us doing track time upgraded BBKs allow later/deeper braking and consistent brake feel.

I personally run Alcon 355mm directional rotors front 310mm rear Alcon rotors with potorfield R4S pads f&r and Nitto NT05 tires on the street. I run a separate set of alcon rotors with Carbotech XP10/12 pads front & rear with yoko R compounds for track days.

The key is to have proper pads and tires for the conditions. I keep Nokian Hakka R tires with Carbotech bobcats on my winter vehicle.

[Charles.waite]

I did mean DOT 4.

IMHO,
I am big fan of stock brakes(maybe cause I am frugal) but I honestly believe the engineers that designed our cars know what they are doing. BBK tends to mess up the balance of the car. With me its all about balance.

Having experience in track racing(go-karts, time trials, autocrossing, gymkhana, and drifting), you really only need big brakes if you are driving to the limit AND have sticky tires. I see guys everywhere who have big brakes but crappy tires.
It really defeats the purpose, cause you can have the biggest 6 Pot calipers with the best rotors, paired with crappy tires, you wont be stopping anywhere and flat spotting your tires.

With respect to the Cross Drilled/Slotted, my experience with them is that if you are going with a stock setup(A4/S4/Toureg), then stick with Stock thick blanks.
Your brakes are only as good as the amount of surface area the brake pads come into contact with the rotor. With Cross Drilled/Slotted, the surface area of the pad to rotor contact is severely compromised by at least 10%. On top of that, your structural integrity is also compromised, hence why Drilled/Slotted rotors have a much higher (almost tripled) propensity to crack/fail.
The other portion is the cost of the Drill/Slot Rotors are almost 40-50% more expensive.

Just like with everything else, its all about a pissing contest, and who has the biggest BBK etc, which I dont get or participate.

I choose functionality without compromising safety or performance any day.

On my current B6 with stock rotors and calipers, coupled with SS lines, DOT 4 fluid, Porterfields R4S Pads, and very sticky Hankook RS3 Tires, I have out braked my other friend's Stock B6 S4, stock B7 S4 numerous times at the track and in the mountains.
For the Daily Grind, I probably have avoided so many accidents, and at the same time brakes work so good, that you could literally brake check someone as you would be able to outbreak alot of car that are on the streets.
This is cheapo setup is cause you are just making the stock stuff work smarter and better.

Big brakes are nice and all, but for an average Lee(i'm asian) like me, stocks brakes work just perfect.

If your friends didn't have the same tires, then of course you'll out brake them. I'd love to see the brake fade the stock setup would see on the track though. Yikes...